A variety of proposals have been made for this kind of discharge lamp to substitute it for an incandescent lamp because the discharge lamp allows its size-reduction into a compact form. The discharge lamp disclosed in Japanese Unexamined Patent Publication No. 44956/1982 is shown in FIG. 1 as an example, in which there are provided two electrodes 3 passing through an end plate 2 closing the lower opening portion of an outer bulb 1, extending in the outer bulb 1 and each one end of inner tubes 4, formed into a U-shape, is fitted to each projection 11 through which each of the electrodes 3 passes, on account of which cross-talk discharge possibly occurring between the electrodes 3 is prevented. The other open end of the inner tubes 4 is in contact with the upper surface of the end plate 2 and a recess 5 for causing bridge of electric discharge is formed in the vicinity of each of the open ends. On the other hand, the inner tubes 4 are held by a pressing plate 10 fitted to the upper end of a supporting rod 9 secured to the end plate 2 so that both the open ends are in contact with the end plate 2. A reference numeral 7 designates a layer of fluorescent material.
In the discharge lamp having the construction described above, since the supporting rod 9 and the pressing plate 10, both needed to secure the inner tubes 1 are incorporated in the lamp as additional parts, there are problems of increasing the number of parts; causing additional management for these parts, complicated structure of the lamp and increasing manufacturing steps.